Apparatus and Delivery of Oxygen

ABSTRACT

Disclosed are various aspects of an oxygen generator and a method of oxygen generation. In certain embodiments, the oxygen generator comprises a reaction chamber, a humidifier, and a cap assembly.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims the benefit of thefiling date of U.S. patent application Ser. No. 10/856,591 entitled“APPARATUS AND DELIVERY OF MEDICALLY PURE OXYGEN” (Docket No. 2934000),filed on May 28, 2004, the disclosure of which is incorporated herein byreference for all purposes. This application also relates to aco-pending U.S. patent application Ser. No. 10/718,131 entitled “METHODAND APPARATUS FOR GENERATING OXYGEN” (Docket No. ROSS 2864000), filedNov. 20, 2003, the disclosure of which is hereby incorporated byreference for all purposes.

TECHNICAL FIELD

The present invention relates generally to the production of medicallypure oxygen and, more particularly, to apparatus and methods of deliveryof medically pure oxygen.

BACKGROUND INFORMATION

Oxygen generators using chemical reactions have been known for sometime, and the principles governing the chemical reaction driving theoxygen production are well documented. However, none of the conventionaldevices relating to chemical oxygen generators have resulted inmedically pure oxygen becoming an easily accessible, inexpensive,over-the-counter consumer item, nor have they resulted in it becoming astandard-issue item for public and private emergency-response personneland locations. In addition, conventional generators have not been widelyadopted in commerce and industry. There are several possible factorscontributing to this lack of interest, including one or a combination ofunfavorable characteristics relating to reusability, safety, ease ofuse/operation, speed of use, heat management, cost, weight, aestheticdesign, environmental impact, manufacturability, portability, medicalefficacy, effectiveness, flow rate, oxygen yield, reaction stability,and oxygen purity. Some or all of these characteristics are notaddressed, or are inadequately addressed, by conventional devices.

Conventional designs have not adequately addressed elimination of heatgenerated by the exothermic chemical reaction involved, withoutadversely affecting other factors such as cost and weight, for example.The heat generated by the chemical reaction can prevent the user fromhandling the generator itself with bare hands, either during orimmediately following the reaction cycle. Efforts to address thisshortcoming have reduced the portability and utility of the product.

Another issue is related to flow rate and to total oxygen yield.Conventional designs have not adequately addressed the associatedconsequences of more stringent performance requirements for flow rateand total oxygen yield, particularly in emergency and safetyapplications where higher flow rates are required, and, in some casesmandated by regulatory authorities. For example, the United States Foodand Drug Administration (FDA) has long required a flow rate performanceof at least 6 liters per minute over 15 minutes in order to obtainmarket clearance for over the counter purchase, resulting in a totaloxygen yield requirement of 90 liters. Higher flow rates over asustained period typically are accompanied by increased heat beinggenerated by the chemical reaction. In addition, higher pressures beinggenerated inside the reaction chamber generally accompany higher flowrate outputs or requirements.

The reaction chamber is a closed environment with typically at least one“exit point” for the oxygen generated. The higher pressure causes theaqueous reaction mixture to advance in the same direction and under thesame pressure conditions as the oxygen being generated. A consequence isthe dangerous possibility that some of the aqueous reaction mixture orsome of the particles from the chemical reaction components will travelwith the oxygen generated, into the user's lungs. Higher flow rates canalso result in leakages and consequently safety concerns.

Therefore, a need exists for a method and/or apparatus for producingmedically pure oxygen that addresses at least some of the problemsassociated with conventional methods and apparatus for producingmedically pure oxygen.

SUMMARY

Disclosed are various aspects of an apparatus for delivering medicallypure oxygen and methods for generating oxygen. An inner sleeve thatcontains an oxygen producing chemical reaction. The inner sleeve iscontained within an outer housing. An insulating space or layer isinterposed between at least a portion of the sleeve and housing. Anoxygen transmission channel extends from and is in fluid communicationwith the contents of the inner sleeve.

In one aspect of the invention, a humidifier coupled to the oxygentransmission channel humidifies and filters the oxygen.

In another aspect of the invention, a cap holds together the sleeve andhousing.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front elevation view of the assembled generator dispenseraccording to certain aspects of the present invention;

FIG. 2 is a sectional view along 2-2 of FIG. 1;

FIG. 3 is a perspective view of the exploded or disassembled componentsof the generator dispenser according to certain aspects of the presentinvention;

FIG. 4 is a front elevation view of the exploded or disassembledcomponents of the base of the generator, comprising the reaction chamberexterior housing and the reaction chamber inner sleeve;

FIG. 5 is a perspective top view of the reaction chamber exteriorhousing and the reaction chamber inner sleeve;

FIG. 6 is a sectional front view of the assembled reaction chamberexterior housing and the reaction chamber inner sleeve along 6-6 in FIG.4;

FIG. 7 is a perspective view of the humidifier assembly;

FIG. 8 is a front elevation view of the exploded or disassembledcomponents of the humidifier assembly, comprising the humidifier bodyand the humidifier base;

FIG. 9 is a sectional front view of the humidifier assembly along 9-9 inFIG. 7;

FIG. 10, FIG. 11 and FIG. 12 are perspective views of the humidifierbase from different angles;

FIG. 13 is a view on section 13-13 of FIG. 11;

FIG. 14 is a perspective view of the exploded or disassembled componentsof the humidifier assembly and the membrane stack;

FIG. 15 is a perspective view of the exploded or disassembled componentsof the membrane stack;

FIG. 16 is a front elevation view of the humidifier body;

FIG. 17 and FIG. 18 are perspective views of the top and the bottom,respectively of the humidifier body;

FIG. 19 is front elevation view of the cap of the generator dispenser;

FIG. 20 is a view on section 20-20 of FIG. 19;

FIG. 21 is a perspective view of the exploded or disassembled componentsof the cap and “outer stem” assembly;

FIG. 22, FIG. 23 and FIG. 24 are perspective views of the “outer stem”;

FIG. 25 is a view on section 25-25 of FIG. 24;

FIG. 26 is a front elevation of the cap of the generator dispenser;

FIG. 27 is a perspective view of the bottom of the cap of the generatordispenser.

DETAILED DESCRIPTION

In the following discussion, numerous specific details are set forth toprovide a thorough understanding of the present invention. However,those skilled in the art will appreciate that the present invention maybe practiced without such specific details. In other instances,well-known elements have been illustrated in schematic or block diagramform in order not to obscure the present invention in unnecessarydetail.

Referring now to FIGS. 1, 2 and 3 of the drawings, a dispenser is showncomprising a reaction chamber exterior housing 100, a reaction chamberinner sleeve 150 which fits advantageously into the reaction chamberexterior housing 100, a humidifier base 200, a humidifier body 300, anouter stem 360 and a cap 400. These components fit together to form theassembled generator shown in FIG. 1. Also, the outer housing 100 and thereaction chamber are typically cylindrical. The reaction chamber innersleeve 150 slides into the reaction chamber exterior housing 100 asillustrated by FIG. 4. The reaction chamber inner sleeve 150 can thenadhere to the reaction chamber exterior housing at a lip boundary 152 inFIG. 2. Adherence of the reaction chamber to the can be accomplishedthrough a variety of methods that include, but is not limited to,chemical bonding (such as epoxy) and thermal fusing (such as welding ormelting together).

Additionally, the reaction chamber exterior housing 100 and the reactionchamber inner sleeve 150 can also be adhered to each other at variousother locations. More particularly, the reaction chamber inner sleeve150 at any point of contact with exterior housing 100, or the reactionchamber inner sleeve 150 and the reaction chamber exterior housing 100can also be manufactured as one single component. By having the reactionchamber 150 and the exterior housing 100 manufactured as a singlecomponent, the need for an adhesive can be eliminated, and the integrityand strength of the reaction chamber 150 can be increased.

The reaction chamber 150 can also incorporate a “draft” into its design.A draft can facilitate or support a plastic injection molding process asa means of commercial production. For example, the draft can include a1.5-degree angle between the vertical plane and the plane of thereaction chamber exterior housing as shown in FIG. 1. Other angles canalso be employed. However, the reaction chamber inner sleeve 150 willtypically employ the same draft angle as the reaction chamber exteriorhousing 100.

The sides of the reaction chamber inner sleeve 150 and the sides of thereaction chamber exterior housing 100 are separated from one another bya series of side ribs 160 illustrated in FIG. 5, attached to and placedequidistantly around the surface of the reaction chamber inner sleeve150. The side ribs 160 can also be attached to and placed equidistantlyaround the surface of the reaction chamber exterior housing 100.However, if a plastic injection molding method of commercial productionis used, then these side ribs 160 may cause “shadows” on the outersurface of the reaction chamber exterior housing 100, thereby causingadverse aesthetic effects. The bottom of the reaction chamber innersleeve 150 and the bottom of the reaction chamber exterior housing 100are separated from each other by a series of bottom ribs 120 illustratedin FIG. 5 and FIG. 6.

These bottom ribs 120 can be designed to extend radially from thecylindrical axis of the outer housing (not shown) and are attached tothe inside bottom of the reaction chamber exterior housing 100. FIG. 2and FIG. 6 illustrate how the design creates a space 154 between thereaction chamber inner sleeve 150 and the reaction chamber exteriorhousing 100. This space creates a very effective “air insulator”,serving to reduce, minimize or prevent the heat generated from theexothermic chemical reaction inside the reaction chamber inner sleeve150 from reaching the outer surface of the reaction chamber exteriorhousing 100. The air insulation created by the space 154 illustrated inFIG. 2 and FIG. 6 is significantly effective in ensuring that the userof the oxygen generator can comfortably and safely handle the generatordirectly with bare hands, during, or after the chemical reaction cycle.

The side ribs 160 typically extend from the lip boundary 152 to a pointjust above the position of the bottom ribs 120. Essentially, the sideribs 160 provide a contact surface between the reaction chamber outerhousing 100 and the reaction chamber inner sleeve 150 nearly parallel tothe cylindrical axis to reaction chamber outer housing 100 and thereaction chamber inner sleeve 150. However, because the side ribs 160are at and below the lip boundary 152, the ribs are hidden from viewonce assembled. A reason for having side ribs 160 and bottom ribs 120 isto provide spaces 154 or an insulation gap between the reaction chamberinner sleeve 150 and the reaction chamber outer housing 100 that willlimit, reduce or otherwise minimize the transfer of heat between theinside of the reaction chamber inner sleeve 150 and the outer surface ofthe reaction chamber outer housing 100, thereby enhancing the ability ofthe user to comfortably operate the generator with bare hands, bothduring and upon completion of the chemical reaction cycle.

In addition to creating the spaces 154 illustrated in FIG. 2 and FIG. 6,which serve as an effective “air insulator,” the ribs 120 and 160illustrated in FIG. 5 also serve to significantly strengthen thereaction chamber by reinforcing both the reaction chamber exteriorhousing 100 and the reaction chamber inner sleeve 150. A much moreeffective resistance to pressure build-up (during the chemical reaction)can then be provided inside the reaction chamber than is currentlyprovided. The use of ribs 120 and 160 would provide additional materialto combat stress, strain, and, possibly, torsion that result frominternal pressures by improving the tensile strength of the reactionchamber.

As an additional example, an additional material can be utilized insteadof air. A material, such as a high strength epoxy can fill the gap thatresults from the separation between the reaction chamber 150 and outerhousing 100. Thus, a single wall design with an inserted material wouldthen have similar strength properties to one with an air gap, but alsohave the benefit of being completely solid.

Because the reaction to produce oxygen is an exothermic reaction,insulation from the reaction is desirable. The heat transfer from thechemical reaction to the surface of the reaction chamber exteriorhousing 100 can be further reduced or minimized by the materialselection for the reaction chamber exterior housing 100 and the reactionchamber inner sleeve 150. Typically, each of the materials chosen has anR-factor above about 1.5. For example, the reaction chamber inner sleeve150 can be made of Polycarbonate, and the reaction chamber exteriorhousing 100 can be made of Acrylonitrile Butadiene Styrene. Otherplastics or materials such as Polypropylene or Polyethylene can also beused for either the reaction chamber exterior housing 100, or thereaction chamber inner sleeve 150.

The selection of Polycarbonate for the reaction chamber inner sleeve 150is particularly advantageous for the physical properties of thismaterial. Polycarbonate is a tough, dimensionally stable, transparentthermoplastic that is well suited to applications that demand highperformance properties. From a commercial production point of view,Polycarbonate is widely available and accessible, and constitutes aversatile thermoplastic, which maintains its properties over a widerange of temperatures. Polycarbonate has the highest impact strength ofany thermoplastic, and has outstanding dimensional and thermalstability, high tensile strength, good chemical resistance, exceptionalmachinability, low thermal conductivity and is non-toxic with low waterabsorption. The selection of Acrylonitrile Butadiene Styrene for thereaction chamber exterior housing 100, on the other hand, isadvantageous for its lower (than Polycarbonate, for example) cost, whileproviding a rigid thermoplastic material that has high impact strength,high tensile strength and good machinability. However, there are also avariety of other polymers, plastics, and composite materials that can beused.

Furthermore, various wall thicknesses can be used for the reactionchamber exterior housing 100 and the reaction chamber inner sleeve 150.Examples for the wall thicknesses for the reaction chamber exteriorhousing 100 and the reaction chamber inner sleeve 150 include 0.093inches and 0.125 inches respectively. However, the thickness of thewalls can be varied according to either desire or need that is based onsuch considerations as the materials chosen and the thermal output ofthe reaction.

Referring to FIG. 7, FIG. 8 and FIG. 9, the humidifier base 200 isremovable from the humidifier body 300. The humidifier base 200incorporates inner thread (female) 202, which mates with the outerthread (male) 302 incorporated in the humidifier body 300 for easy andrapid unscrewing to remove and screwing back to replace. Three turns ofinner thread 202 and outer thread 302 relative to each other can beused.

Once the humidifier base 200 and the humidifier body 300 are assembled,a plenum 250 is created. This plenum 250 is used to house the membranestack 260, illustrated in FIG. 14 and FIG. 15. The removability of thehumidifier base 200 allows for easy inspection of the membrane stack 260housed in the plenum 250. In addition, the removability of thehumidifier base 200 allows for easy and frequent replacement of any orall of the components of the membrane stack 260 housed in the plenum250. Also, both the humidifier base 200 and the humidifier body 300 canbe made of Polycarbonate or another polymer.

Referring to FIG. 10, FIG. 11, FIG. 12 and FIG. 13, the design of thehumidifier base 200 includes an annular faceplate 208, whichincorporates porosity, as to allow increased airflow to pass through tothe plenum 250. The annular faceplate 208 also serves to rigidly supportthe membrane stack 260 above it.

The annular faceplate 208, however, can affect the airflow. Enhancedporosity can be achieved, for example, through circular apertures 210 inthe annular faceplate 208. The shape of the apertures 210, however, canvary. The apertures 210 can be made sufficiently large in order tominimize any clogging of the membranes supported above the annularfaceplate 208. Another way to prevent membrane clogging and to improvethe performance of the membrane housing, in general, is to vary thecontact angle with the air flow of the annular faceplate 208. An exampleis to vary the angle from 90° to something less than 90°, such as 65°.

The humidifier base 200 also incorporates several other features. A“grip detail” 212 is provided, which allows for enhanced grip (whenremoving/unscrewing or tightening) and easier user handling. A thread“lead-in” 214 is also provided to allow for faster and easiertightening. The thread lead-in 214 is a gap that extends above the innerthread (female) 202, so that when coupled with the outer thread (male)302 there is not an immediate need for threading. In addition, thehumidifier base 200 is reinforced with a series of angular ribs 204 toprovide additional rigidity and strength to resist the upward pressurefrom the direction of the airflow and chemical reaction.

Utilizing a membrane stack 260, as illustrated in FIG. 14 and FIG. 15,improves filtration efficiency significantly. The different componentsof the membrane stack 260, however, serve different functions. The firstcomponent of the membrane stack 260 consists of a pre-filter 222, therole of which is to remove or retain the majority of any chemicalreaction particles or aqueous chemical solution and prevent same fromentering or reaching the second tier of the membrane stack.

The pre-filter 222 is cost-effectively replaceable after every singlechemical reaction or after every single use of the oxygen generator. Theusage and lifespan of the other, more expensive, membranes in the stackcan, thus, be increased due to the replacability of the pre-filter.Examples of pre-filters that can be used include glass fiber filterpapers or binder-free glass microfiber filters. However, there are avariety of materials that can be utilized to form the pre-filters. Themost practicable size for the pores of the pre-filter 222 isapproximately 10 microns. The pre-filter 222 can also be preceded by a“foam-breaker”, which could be a stainless steel mesh and can serve tofilter coarse particles.

The functions of the second membrane 224 are to provide rigid supportfor the main phase separation membrane 226 and to provide additionalfiltration. During the chemical reaction, the airflow can exertsignificant pressure on the membranes. These pressures exerted onmembranes used to separate the oxygen from any chemical reactioncomponents/particles and any aqueous chemical solution can be very high,especially at the higher flow rates above 6 liters per minute. Thesecond membrane 224 consists of a porous plastic and can be 0.250 inchesthick. However, a variety of other materials and thicknesses can beemployed.

The porous plastics used in the second membrane 250, however, contain anintricate network of open-celled, omnidirectional pores. These pores,which can have average pore sizes as low as one micron, give porousplastics their unique combination of filtering capability and structuralstrength. Unlike the direct passages in woven synthetic materials andmetal screens, the pores in porous plastic join to form many tortuouspaths. Porous plastics have dual filtering capability. Not only do theyact as surface filters by trapping particles larger than their averagepore size, they also trap much smaller particulate matter deep in theircomplex channels, for a “depth filter” effect. Therefore, the efficiencyof this tortuous path structure is such that porous plastics with anaverage pore size of 25 microns offer approximately the same filtrationas five micron-rated filter media. The most practicable size for thepores of the second membrane 224 appears to be 10 microns, although apore size rating of 10 microns through 30 microns can also be used.

The third membrane 226 provides final separation of the oxygen and anyremaining aqueous solution or particle matter, resulting in medicallypure oxygen being passed through to the humidifier 300. This thirdmembrane 226 is designed to be inherently hydrophobic for aqueousclarification and particulate capture. Also, the third membrane 226should be compatible with strong acids and aggressive solutions andshould be consistent with high flow rates for faster filtration Superiordurability is also desirable.

The pore sizes for the third membrane 226 are usually smaller than theother membranes. Suitable pore sizes for the third membrane 226 canrange anywhere from 0.1 microns to 10.0 microns, depending on flow ratesdesired. Examples of membranes that can be used includePolytetrafluoroethylene and Nylon membranes; however, a variety of othermaterials can also be used to form the membranes.

The fourth membrane 228 provides optional “downstream” support for thethird membrane 226. It can consist of a porous plastic. Examples mayinclude a 0.125 inch thick Polytetrafluoroethylene porous plastic,although other materials and thicknesses can be used.

FIG. 14 and FIG. 15 also show an annular disc 230. The annular disc 230is designed to provide downstream rigid support for the membrane stack260. The annular disc 230 provides for maximum oxygen flow into thehumidifier body 300 through a series of apertures 232. Also, the annulardisc 230 can be adhered to the annular face 252, shown in FIG. 18.Adhering the annular disc 230 to the annular face 252 ensures that usersdo not inadvertently forget to replace the annular disc 230 afterremoving the membrane stack 260 for inspection or replacement purposes.

FIG. 18 illustrates an aperture 308 through which the purified oxygenflows into the inner stem 350, also shown in FIG. 17. The supportprovided by the annular disc 230 can ensure that the pressurizedairflow, particularly at high flow rates, does not cause the membranesto bow into or be forced into aperture 308. The annular disc 230 can bemade of Polycarbonate. The diameters of the membrane stack 260 and ofthe annular disc 232, both of which can vary, are selected in thisinvention to be 47 mm in diameter.

Referring to FIG. 16, FIG. 17, and FIG. 18, the humidifier body 300 hasan annular flange 310. The annular flange 310 isolates the reactionchamber formed by the reaction chamber inner sleeve 150. By isolatingthe reaction chamber, most of the chemical reaction can be sealed off asthe annular flange 310 seats advantageously on the flat circular surfaceof the lip 156 at the top of the reaction chamber inner sleeve 150 shownin FIG. 5. The annular flange 310 is then reinforced with bottom ribs304 and the top ribs 306, arranged axially to increase rigidity. Thebottom ribs 304 and the top ribs 306 are staggered in terms of theirplacement opposite each other. For example, if the top ribs 306 arespatially arranged to be located at 0°, 90°, 180°, 270°, then the bottomribs 304 are arranged to be at 45°, 135°, 225° and 315°, as illustratedin FIG. 16.

The staggered design further enhances the reinforcement effect of theribs on the annular flange 310. By having ribs, such as the bottom ribs304, staggered, there are no extended surfaces that can deform, bow,crack or move as a result of pressures. The ribbed design alsoeffectively counteracts the upward pressure on the annular flange 310 bythe positive pressure generated during the chemical reaction.

The humidifier body 300 also has predetermined minimum and maximum waterlevels 320 and 322, respectively. The minimum and maximum water levels320 and 322, respectively, provide an easy, viewable guide, allowing theuser to fill the humidifier body 300 with water to a pie-determinedlevel prior to commencing the chemical reaction. The primary purpose ofthe water in the humidifier body 300 is to hydrate the oxygen produced.This hydration is achieved when the oxygen, flowing in a downwarddirection inside the outer stem 360 (FIG. 21) is diffused by the slats362 (FIG. 23). After the diffusion, warm oxygen flows through the wateradded by the user in the humidifier body 300, causing water vapor andoxygen molecules to mix. The slats 362 act as “diffusion ports”,creating improved hydration of the oxygen, while at the same timereducing system back pressure. The humidification process maintains adesirable level of oxygen saturation. The user ultimately breathesmedically acceptable, hydrated oxygen, which translates into oxygen thatis comfortable to breathe and not dry, as can be the case with many“traditional” oxygen devices.

Another component of the humidifier is the inner stem 350. The innerstem 350 is tapered such that the top aperture 352 is smaller indiameter than the diameter of bottom aperture 308, creating a nozzle.The taper effect allows for easy and convenient location of the innerstem 350 by the outer stem 360, shown in FIG. 19 and FIG. 20, uponclosing of the generator by twisting on the cap 400, which is also shownin FIG. 19 and FIG. 20.

The humidifier body 300 also has a series of flat ribs 316 inside at itsbase. These flat ribs 316 are arranged radially from the base of theinner stem 350. These flat ribs 316 have ends 318 that are angledtowards the base of the humidifier body 300. The flat ribs 316 serve tocenter the outer stem 360 upon closing of the generator. The angle ofthe lip 372 at the base of the outer stem 360 forces the outer stem to acenter axial position by mating and fitting advantageously over the ends318 of the flat ribs 316.

FIG. 19 and FIG. 20 illustrate the cap assembly, which includes the cap400 and the outer stem 360. The outer stem 360 is attached to the cap400 at a boundary 370. The outer stem 360 is attached to the cap 400 byadhering it to the sides of the cavity 428 at 370, as illustrated byFIG. 20. Alternatively, the cap assembly consisting of cap 400 and theouter stem 360 can be manufactured (using a process such as injectionmolding) as one piece. An advantage to the user of having the capassembly as one piece is that it significantly facilitates rapid closureof the generator, while at the same time sealing off the humidifier andpositioning the inner stem 350 and outer stem 360 correctly. Having asingle cap 400 and outer stem 360 comprise a single piece isparticularly helpful in medical emergency situations, where time is ofthe essence, and precious seconds can make a difference in saving alife.

Independently, the outer stem 360 has a bottom aperture 364 (shown inFIG. 23), and is tapered to match the taper angle of the inner stem 350.The bottom of the lip 374 of the outer stem 360 is flat and makescontact with the inside base of the humidifier body 300 upon closure ofthe generator. In addition, the surface 376 rests on the bottom ribs 316once the generator is closed for additional stability and to prevent any“rattling” or “vibration” due to the oxygen flow during the reaction.

At the base of the outer stem 360 there are several slats 362, locatedsubstantially equidistant apart, as is shown in FIG. 22 and FIG. 23.These slats 362 allow for oxygen to pass through at high flow rates.However, apertures or holes can also be used instead of slats. The slats362, though, cause the oxygen flowing through them to be diffused,providing superior oxygen hydration while at the same time facilitatingquiet operation and reducing system back pressure. Toward the top of theouter stem 360 there is a flow barrier 366 that acts as a shut-off. Thetop of the outer stem 360 is designed to mate into the cavity 428, asshown in FIG. 27.

Referring to FIG. 26 and FIG. 27, the cap 400 has outer threads 402,which mate with the inner thread 112 of the reaction chamber exteriorhousing 100, creating an airtight seal. While any number of threads canbe used, typically no more than three turns are preferred for fasterclosure. Inserting a gasket (not shown) or an 0-ring (not shown) betweenthe cap 400 and the reaction chamber 150 can further enhanceair-tightness.

Additionally, the cap 400 has flange 404, which seats on the top ofreaction chamber exterior housing 100 upon closure of the dispenser. Thethread 402 is accommodated in such a manner as to allow the inside wallof the reaction chamber inner sleeve 150 to be substantially flush withthe inside wall surface 430 of cap 400 by the use of a bell housingdesign 110, as illustrated in FIG. 4. The cap 400 further has exteriorribs 406, serving the functional purpose of facilitating user grip (fortwisting/closing or untwisting/opening of the cap 400), as well asserving an aesthetic purpose.

The cap 400 also includes some other features. By designing the cap 400with the insets 412, the user is able to more easily handle the cap 400,even if the user has smaller hands. The cap 400 has a recessed nippleoutlet 410 through which the oxygen is expelled. The user can attach atube (attached to a CPR mask) or cannula to the recessed nipple outlet410.

Underneath the cap 400 there is a cavity 420, which completes the tophalf of the humidifier. The inside wall forming the cavity 420 and theinside wall of humidifier body 300 are preferably substantially flushupon closure. The substantial flushness is achieved through an offset422, such that the top edge 362 of the humidifier body 300 slides intothe offset 422 upon closure, coming to rest at 424 and sealing off thehumidifier from the rest of the generator. The cap 400 can be made ofclear Polycarbonate.

Once closed and the chemical reaction has commenced, the oxygen isexpelled from the membrane stack 260, which flows through the annulardisc 230, and enters the humidifier body 300 through inner stem 350 viathe inlet provided by aperture 308. The oxygen exits the inner stem 350at its top aperture 352, proceeding away from the reaction chamber 150.The oxygen is then forced into the opposite direction, toward the baseof the humidifier body 300, by the flow barrier 366 located towards thetop of the outer stem 360. The oxygen flows to the bottom of outer stem360 and exits through the slats 362. At this point, the oxygen entersthe water inside the humidifier body 300, bubbling through the water andbeing hydrated in the process. The hydrated oxygen can then proceed intoplenum 426. The oxygen then enters the top of the outer stem 360 throughthe slats 368, as shown in FIG. 24, enters plenum 428, and then exitsthe generator through the recessed nipple outlet 410.

It is preferable to maintain control of the flow of oxygen. For thispurpose, valve (not shown) can be used to regulate the flow of oxygenout of the cap 450. A variety of types of regulator valves can beutilized to control the flow of oxygen. Preferably, such a regulatorvalve would be coupled to the nipple 410 of the cap 450. Alternatively,a pressure regulator could be used in place of a regulator valve, toautomatically adjust the pressure or flow rate of expelling oxygen to adesired set point or range.

Additionally or alternatively, oxygen flow rates can be controlled orregulated by varying the number or thickness of the layers of coatingcovering the particles of the oxygen releasing agent (usually in powderform) used in the chemical reaction. Flow rates can also be controlledthrough selection of the particle size of oxygen releasing agent.Clearly, flow rates can also be controlled through a combination ofthese three factors.

It is understood that the present invention can take many forms andembodiments. Accordingly, several variations may be made in theforegoing without departing from the spirit or the scope of theinvention. The capabilities outlined herein allow for the possibility ofa variety of programming models. This disclosure should not be read aspreferring any particular programming model, but is instead directed tothe underlying mechanisms on which these programming models can bebuilt.

Having thus described the present invention by reference to certain ofits preferred embodiments, it is noted that the embodiments disclosedare illustrative rather than limiting in nature and that a wide range ofvariations, modifications, changes, and substitutions are contemplatedin the foregoing disclosure and, in some instances, some features of thepresent invention may be employed without a corresponding use of theother features. Many such variations and modifications may be considereddesirable by those skilled in the art based upon a review of theforegoing description of preferred embodiments. Accordingly, it isappropriate that the appended claims be construed broadly and in amanner consistent with the scope of the invention.

1. A method for generating oxygen, comprising: providing an exteriorhousing, sliding a portion of a sleeve having a reaction chamber withinthe exterior housing, generating an oxygen gas flow from a chemicalreaction positioned within the reaction chamber, directing the oxygengas flow through a foam breaker positioned within a reaction chamber,separating a first portion of chemical reaction particles from theoxygen gas flow with a pre-filter, supporting the pre-filter with afirst structural support positioned within a pathway of the oxygen gasflow, directing the oxygen gas flow through openings in the firststructural support, separating a second portion of chemical reactionparticles from the oxygen gas flow with a hydrophobic membrane removingparticles having an average pore size in the range of substantially 0.1to 10 microns, supporting the hydrophobic membrane with a secondstructural support positioned within a pathway of the oxygen gas flow,directing the oxygen gas flow through a plurality of openings in thesecond structural support, directing the oxygen gas flow through ahollow structure having an inlet opening and at least one exhaustopening positioned within a water basin, humidifying the oxygen gas flowby directing the oxygen gas flow through water contained in the waterbasin, and directing the oxygen gas flow through a plenum in fluidcommunication with humidifier system and positioned within the pathwayof the oxygen gas flow.
 2. The method of claim 1, wherein the directingthe oxygen gas flow through a hollow structure further comprises:channeling the oxygen gas stream through an inner hollow stem, turningthe oxygen gas stream using an outer stem enclosing a portion of theinner hollow stem, directing the oxygen gas stream through exhaust slitsin the wall of the outer stem, and directing the oxygen gas stream intoa predetermined amount of water in a water holding basin.
 3. The methodof claim 1, wherein the directing the oxygen gas flow through a plenumfurther comprises directing the oxygen gas stream through an outerplenum in fluid communication with the water basin, the outer plenumformed in an interior space of an exterior cap having an opening forcoupling to the exterior housing and an opening for exhausting a gas. 4.The method of claim 1, wherein the separating a first portion furthercomprises removing particles having an average size of greater than 10microns by channeling the oxygen gas stream through the pre-filter.